GTEs produce power by extracting energy from a flow of hot gas produced by combustion of fuel in a stream of compressed air. In general, turbine engines have an upstream air compressor coupled to a downstream turbine with a combustion chamber (“combustor”) in between. Energy is released when a mixture of compressed air and fuel is burned in the combustor. In a typical turbine engine, one or more fuel injectors direct a liquid or gaseous hydrocarbon fuel into the combustor for combustion. The resulting hot gases are directed over blades of the turbine to spin the turbine and produce mechanical power.
In high performance GTEs, a portion of the compressed air is used to cool GTE components, for example turbine components, exposed to hot gas flow. GTEs include cooling passages and cooling flows for receiving the portion of compressed air to improve reliability and cycle life of individual components within the GTE. GTE components, such as stationary turbine guide vanes, commonly referred to as turbine nozzles, are arranged such that the portion of compressed air flows through a plurality of internal cooling passages of the turbine nozzles.
U.S. Pat. No. 7,836,703 to Lee et al. (the '703 patent) describes a cooled turbine nozzle assembly. According to the '703 patent, the assembly may include an annular turbine nozzle 20 including alternating pairs of first and second stator vanes 36, 38 arranged in pairs in nozzle doublets. Each of the first and second stator vanes 36 and 38 includes a varying cooling circuit 63, 64 inserted within stator vanes 36 and 38, respectively, so as to affect cooling in conjunction with a circumferential “clocking” of individual fuel injectors to avoid hot streaks.